Hi together,
maybe it's the hull of Sondergerät SG 113 "Förstersonde", a special weapon used to shoot vertically 2+2 missiles downwards on tanks when flying over them. Rockets were automatically released when passing the tanks by a fluxgate-magnetometer - in german "Förstersonde" named as its inventor Friedrich Förster.
Here an example mounted to a FW190 F-8:
View attachment 608192View attachment 608193View attachment 608195
Manufacturer Rheinmetall-Borsig/Hermann-Göring-Werke, caliber barrel 7,7cm, caliber projectile 4,8cm, armor piercing (tungsten core), weight projectile 1,9kg, weight complete unloaded 48kg. complete length 1650mm, length of barrel 1600mm, muzzle speed 650 m/s, recoilless.
Would be quite a rare part, if it would match, no doubt!
Hope it helps.
Spielkind